Quantum cryptography

Illustration for Swedish science magazine Forskning & framsteg - on how quantum mechanichal properties may be used to perform cryptographic tasks. Visualized here as a letter/ e-mail-carrier in the form of Schrödinger's cat*

* Schrödingers cat was a thought experiment devised by the physicist Erwin Schrödinger, where a cat in a sealed container may simultaneously be both alive and dead as a result of being linked to a random subatomic event that may or may not occur. This since quantum theory dictates that objects such as an atom or a photon can exist in multiple states simultaneously - a principle known as quantum superposition.